Audi A4 Dashboard Warning Lights, Symbols and Meanings
The Audi A4 uses red lights for problems that need you to stop and amber lights for faults to service soon. Two that are specific to Audi and Volkswagen are the EPC light, for electronic power control, and the check-engine light, which often appear together.
Red lights: stop and check
These need action before you keep driving.
Oil Pressure
Engine oil pressure is low.
What to do: Stop safely and check the oil level.
Coolant Temperature
The engine is overheating.
What to do: Pull over and let it cool before checking coolant.
Brake System
Low brake fluid or a brake fault.
What to do: Check fluid and the parking brake, then have it inspected.
Charging System
The battery is not charging.
What to do: Have the charging system checked promptly.
Amber lights: service soon
You can usually keep driving, but book a check.
Check Engine
The engine computer stored a fault.
What to do: Have the codes read. Flashing means a misfire, so slow down.
EPC
An Electronic Power Control fault, often with reduced power.
What to do: Have it scanned soon, as the car may limit power to protect itself.
ABS
The anti-lock brakes have a fault.
What to do: Normal brakes still work, but get ABS checked.
Tire Pressure
A tire is low.
What to do: Inflate all tires to the door-jamb pressure.
Stability / ESP
Stability control is off or has a fault.
What to do: Restart to reset. If it stays, have it scanned.
Power Steering
The steering system reduced assist.
What to do: Restart the car, and if it stays on, have it checked.
About the Audi EPC light
EPC stands for Electronic Power Control, and it manages the throttle, cruise control and stability systems. When the EPC light comes on, usually with the check-engine light, the car often drops into a reduced-power limp mode to protect itself. Common triggers are a throttle-body or accelerator-pedal sensor, a brake-light switch, or an ignition-coil fault. Because it disables full power, do not just clear it and drive on. Have the fault codes read so the repair targets the real cause and the car returns to normal power.
Common questions
What does the EPC light mean on an Audi A4?
EPC is Electronic Power Control. The light means a fault in the throttle or stability system, often with reduced power. Common causes are a throttle-body, pedal or brake-light-switch sensor. Have the codes read to find it.
Why is my Audi A4 in reduced power mode?
Reduced power is a protective limp mode, usually tied to the EPC and check-engine lights from a throttle or sensor fault. Scanning the codes points to the part to fix and restores full power.
Can I drive my Audi A4 with the check engine light on?
If it is steady and the car drives normally, drive gently and get it scanned soon. If it flashes, there is an active misfire, so reduce speed and have it checked right away.